Andrew,
I have the same problem as you stated with memtest86 on my 600SC. I never tested the supplied memory that came with it as I had 2gb of ram waiting when it arrived.
The Crucial ram had similar problems running the check, but I said "what the hell" and loaded RedHat 8 anyway. Installation went without a hitch. I loaded 4.6.2 and had it installed with Postgresql and running the way I wanted in under 4 hours. Followed Joel's new instructions and left out the qmail part.
The machine for the past week has been stable and presents no problems. I'm thinking the error may be an incompatibility with memtest86 and Dell's hardware, but then again Dell could have been dumping hardware with known problems that had failed other tests, no one can know for sure, since we all seem to be seeing the same general errors.
Next week, after Easter I'll find another memtester and try again. But for now, I'm pleased with the 600SC, 2gb Ram, 4-40GB IDE HD's.
